Physical Properties of AZ91D Measured Using the Draining Crucible Method: Effect of SF6

Abstract

The draining crucible (DC) technique was used for measurements on AZ91D under Ar and SF 6 . The DC technique is a new method developed to simultaneously measure the physical properties of fluids, the density, surface tension, and viscosity. Based on the relationship between the height of a metal in a crucible and the outgoing flow rate, a multi-variable regression is used to calculate the values of these fluid properties. Experiments performed with AZ91D at temperatures from 923 K to 1173 K indicate that under argon, the surface tension (N · m −1 ) and density (kg · m −3 ) are [0.63 − 2.13 × 10 −4 (T − T L )] and [1656 − 0.158(T − T L )], respectively. The viscosity (Pa · s) has been determined to be [1.455 × 10 −3 − 1.209 × 10 −5 (T − T L )] over the temperature range from 921 K to 967 K superheat. Above 967 K, the viscosity of the alloy under argon seems to be constant at (2.66 × 10 −4 ± 8.67 × 10 −5 ) Pa · s. SF 6 reduces the surface tension of AZ91D.

A Broad Literature Review of Density Measurements of Liquid Cast Iron

“…The draining crucible method has been developed and used for light metals, i.e., aluminium and magnesium [46,47]. It has the advantage that it is possible to obtain values on surface tension, viscosity, and density from the same measurement.…”

“…The diameter of the orifice must be known accurately in order not to result in significant errors in the property values [46,47]. It is also important that the material at the orifice is non-wetting with regard to the evaluated melt.…”